1. Field
The present disclosure relates to an electronic element package and a method for manufacturing the same.
2. Description of Related Art
Recently, with the recent rapid development of mobile communications devices, the demand for macrofilters, oscillators, and other components has increased. For example, bulk acoustic wave (BAW) resonators have been regularly used to implement macrofilters, oscillators, and other components. Using BAW resonators have advantages such as enabling mass production at low cost and allowing for macrominiaturization. Furthermore, BAW resonators enables a high quality factor to be obtained and may be used in macrofrequency bands.
In general, because performance of resonators (vibrators) of BAW resonators degrade at a bonding temperature of 500° C. or more, the BAW resonators need to be hermetically sealed at a low temperature of 500° C. or less. Thus, thermal diffusion bonding, eutectic bonding or silicon direct bonding may be used. The eutectic bonding includes transient liquid phase bonding.
Furthermore, when applied to a structure having a total thickness value (TTV) difference, the eutectic bonding or the transient liquid phase bonding may cause a bonding surface to be uneven because upper and lower pressure allows a material having a low melting point or an intermetallic compound to be squeezed to run down in a liquid-like state. The unevenness of the bonding surface produces a crack on a region thereof, which causes a reduction in yield of a bonding process in which a hermetic seal is required.
To solve this problem, a method of forming a sufficient amount of melting material as a layer and pressing the layer that fully compensates for a thickness variation is frequently used, but may cause a bonding material to be increased in thickness, and a cost of raw materials rises.